Facile synthesis ultrathin mesoporous Co3O4 nanosheets for high-energy asymmetric supercapacitor

Abstract Highly ultrathin mesoporous Co 3 O 4 nanosheets have been successfully designed and constructed on nickel foam substrate via a facile two-step approach, including a hydrothermal technique without any surfactant and followed calcination of precursor. Owing to the unique mesoporous ultra-thin structural features, the capacitance of Co 3 O 4 nanosheets electrode was as high as 610 mF cm −2  at a current density of 1 mA cm −2 , and the cycling stability remained about 94.5% after 3000 cycles at current density of 4 mA cm −2 . In addition, an asymmetric supercapacitor device based on the ultrathin mesoporous Co 3 O 4 nanosheets was fabricated and has shown promising energy densities of 136 Wh kg −1  at power density of 0.75 kW kg −1 . These results demonstrated that the ultrathin mesoporous Co 3 O 4 nanosheets were excellent candidate for electrochemical supercapacitor devices.